IICRC OCT - REAL QUESTIONS + DETAILED ANSWERS - LATEST
VERSION - TOP RATED 2026/2027
1. What is the primary organ responsible for detecting odors?
• A) Trigeminal nerve
• B) Olfactory epithelium
• C) Nasal septum
• D) Taste buds ANSWER : B
2. How many olfactory receptor cells does the average human have?
• A) 1-5 million
• B) 5-10 million
• C) 10-20 million
• D) 50-100 million ANSWER : C
3. What is the term for the inability to detect odors?
• A) Dysosmia
• B) Anosmia
• C) Parosmia
• D) Hyperosmia ANSWER : B
4. Which nerve transmits olfactory signals to the brain?
• A) Cranial nerve I
• B) Cranial nerve II
• C) Cranial nerve III
• D) Cranial nerve V ANSWER : A
5. What is olfactory fatigue?
• A) Increased sensitivity to odors over time
, • B) Decreased ability to detect odors after prolonged exposure
• C) Permanent loss of smell
• D) Temporary increase in odor perception ANSWER : B
6. Which of the following affects odor perception?
• A) Humidity only
• B) Temperature only
• C) Both humidity and temperature
• D) Neither humidity nor temperature ANSWER : C
7. What percentage of perceived flavor actually comes from smell?
• A) 10-25%
• B) 50-60%
• C) 75-95%
• D) 100% ANSWER : C
8. The trigeminal nerve detects which type of sensations?
• A) Only pleasant odors
• B) Irritating or painful sensations
• C) Sweet smells only
• D) Color perception ANSWER : B
9. What is dysosmia?
• A) Complete loss of smell
• B) Distorted sense of smell
• C) Heightened sense of smell
• D) Inability to taste ANSWER : B
10. How long does it typically take for olfactory fatigue to occur?
• A) 30 seconds to 2 minutes
• B) 5-10 minutes
• C) 30-60 minutes
, • D) 2-4 hours ANSWER : A
11. Which part of the brain processes olfactory information?
• A) Cerebellum
• B) Olfactory bulb and limbic system
• C) Brain stem
• D) Motor cortex ANSWER : B
12. What is the minimum concentration of a substance required for
detection called?
• A) Threshold limit value
• B) Odor threshold
• C) Detection maximum
• D) Sensory ceiling ANSWER : B
13. Why do women generally have a more acute sense of smell than men?
• A) Larger nasal passages
• B) Hormonal differences and more olfactory cells
• C) Smaller brain size
• D) Dietary differences ANSWER : B
14. At what age does sense of smell typically begin to decline?
• A) 30 years
• B) 40 years
• C) 50 years
• D) 60 years ANSWER : D
15. What is phantosmia?
• A) Ability to smell phantom odors that aren't present
• B) Fear of odors
• C) Love of odors
• D) Inability to detect any odor ANSWER : A
16. Which factor does NOT affect individual odor perception?
, • A) Genetics
• B) Previous experiences
• C) Hair color
• D) Health status ANSWER : C
17. What is the term for increased sensitivity to odors?
• A) Anosmia
• B) Hyperosmia
• C) Hyposmia
• D) Normosmia ANSWER : B
18. How does pregnancy typically affect sense of smell?
• A) Decreases sensitivity
• B) Increases sensitivity
• C) No change
• D) Causes permanent loss ANSWER : B
19. Which of the following is a common cause of temporary anosmia?
• A) Common cold
• B) Eye infection
• C) Ear infection
• D) Skin rash ANSWER : A
20. What is the approximate size of the olfactory epithelium?
• A) 1-2 cm²
• B) 2-5 cm²
• C) 5-10 cm²
• D) 10-20 cm² ANSWER : C
21. How often are olfactory receptor cells replaced?
• A) Every 30 days
• B) Every 60 days
VERSION - TOP RATED 2026/2027
1. What is the primary organ responsible for detecting odors?
• A) Trigeminal nerve
• B) Olfactory epithelium
• C) Nasal septum
• D) Taste buds ANSWER : B
2. How many olfactory receptor cells does the average human have?
• A) 1-5 million
• B) 5-10 million
• C) 10-20 million
• D) 50-100 million ANSWER : C
3. What is the term for the inability to detect odors?
• A) Dysosmia
• B) Anosmia
• C) Parosmia
• D) Hyperosmia ANSWER : B
4. Which nerve transmits olfactory signals to the brain?
• A) Cranial nerve I
• B) Cranial nerve II
• C) Cranial nerve III
• D) Cranial nerve V ANSWER : A
5. What is olfactory fatigue?
• A) Increased sensitivity to odors over time
, • B) Decreased ability to detect odors after prolonged exposure
• C) Permanent loss of smell
• D) Temporary increase in odor perception ANSWER : B
6. Which of the following affects odor perception?
• A) Humidity only
• B) Temperature only
• C) Both humidity and temperature
• D) Neither humidity nor temperature ANSWER : C
7. What percentage of perceived flavor actually comes from smell?
• A) 10-25%
• B) 50-60%
• C) 75-95%
• D) 100% ANSWER : C
8. The trigeminal nerve detects which type of sensations?
• A) Only pleasant odors
• B) Irritating or painful sensations
• C) Sweet smells only
• D) Color perception ANSWER : B
9. What is dysosmia?
• A) Complete loss of smell
• B) Distorted sense of smell
• C) Heightened sense of smell
• D) Inability to taste ANSWER : B
10. How long does it typically take for olfactory fatigue to occur?
• A) 30 seconds to 2 minutes
• B) 5-10 minutes
• C) 30-60 minutes
, • D) 2-4 hours ANSWER : A
11. Which part of the brain processes olfactory information?
• A) Cerebellum
• B) Olfactory bulb and limbic system
• C) Brain stem
• D) Motor cortex ANSWER : B
12. What is the minimum concentration of a substance required for
detection called?
• A) Threshold limit value
• B) Odor threshold
• C) Detection maximum
• D) Sensory ceiling ANSWER : B
13. Why do women generally have a more acute sense of smell than men?
• A) Larger nasal passages
• B) Hormonal differences and more olfactory cells
• C) Smaller brain size
• D) Dietary differences ANSWER : B
14. At what age does sense of smell typically begin to decline?
• A) 30 years
• B) 40 years
• C) 50 years
• D) 60 years ANSWER : D
15. What is phantosmia?
• A) Ability to smell phantom odors that aren't present
• B) Fear of odors
• C) Love of odors
• D) Inability to detect any odor ANSWER : A
16. Which factor does NOT affect individual odor perception?
, • A) Genetics
• B) Previous experiences
• C) Hair color
• D) Health status ANSWER : C
17. What is the term for increased sensitivity to odors?
• A) Anosmia
• B) Hyperosmia
• C) Hyposmia
• D) Normosmia ANSWER : B
18. How does pregnancy typically affect sense of smell?
• A) Decreases sensitivity
• B) Increases sensitivity
• C) No change
• D) Causes permanent loss ANSWER : B
19. Which of the following is a common cause of temporary anosmia?
• A) Common cold
• B) Eye infection
• C) Ear infection
• D) Skin rash ANSWER : A
20. What is the approximate size of the olfactory epithelium?
• A) 1-2 cm²
• B) 2-5 cm²
• C) 5-10 cm²
• D) 10-20 cm² ANSWER : C
21. How often are olfactory receptor cells replaced?
• A) Every 30 days
• B) Every 60 days
